


The Physics of Ladybug and Chat Noir

by lizzrossstories



Category: Miraculous Ladybug
Genre: F/M, PHYSICS PUNS, a fanfiction that might actually teach you physics, so many physics puns, this is my way of internalizing what i learned in physics class
Language: English
Status: In-Progress
Published: 2017-06-21
Updated: 2017-08-19
Packaged: 2018-11-16 20:09:18
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 1,908
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11260068
Author URL: https://archiveofourown.org/users/lizzrossstories/pseuds/lizzrossstories
Summary: Marinette could take precise measurements of a model to the hundredth decimal place by sight, could modify ingredient measurements in her head; she could even lasso an akuma halfway to Nice if she wanted to, but she couldn’t for the life of her and all of Paris understand physics. She really was lucky that her partner excelled at it.**THIS FIC IS ON HIATUS UNTIL I FINISH MY THESIS. STAY TUNED FOR MORE CONTENT IN 2019**





	1. This Is Not the Chat You are Looking For

**Author's Note:**

> Lesson 1: Force

Marinette groaned as she repeatedly tapped her forehead to her desk in frustration. She could take precise measurements of a model to the hundredth decimal place by sight, could modify ingredient measurements in her head; she could even lasso an akuma halfway to Nice if she wanted to, but she couldn’t for the life of her and all of Paris understand physics. 

“This is hopeless,” she moaned, trying to make sense of the force diagrams she’d drawn up.

“You’ve got this Marinette!” Tikki replied encouragingly from a small stack of pillows. “Why don’t you try again in a few minutes. Give your brain a break.”

“That’s probably a good idea,” she stretched her arms over her head as she made her way to her chaise and called Alya. 

Alya answered after two rings, “Hey girl, what’s up?”

“Physics. Is. Killing. Me.”

“Oh come on, you just started.”

“I know!” Marinette moaned in anguish. “If this is just the beginning, I’m absolutely fucked for the rest of the class.”

“You just need to figure out how to care about what you’re learning. Physics is supposed to be applicable in everything.”

Leaning against the chaise, Marinette replied, “I don’t think calculating the tension force of the sewing needle and string is really going to help me with designing, Alya.”

Alya laughed, “Well then find something does! Look if you just—”

CRASH

Marinette and Tikki both snapped their heads up at the trapdoor that lead to her balcony. Both the kwami and her charge slowly made their way up to the trapdoor. Placing one hand on the trapdoor above her, Marinette quietly raised it to find a pair of glowing green eyes not two inches away from her face. 

Yelping in surprise, Marinette closed the trapdoor on her head and dropped her phone back down into her room.

“Marinette?” Alya’s voice called. “Is everything alright?”

Scooping up her phone, Marinette quickly replied, “Yeah, sorry Alya I gotta go. I’ll see you tomorrow. Bye!”

“But—”

Marinette threw her phone back onto her bed and lifted to trapdoor once more. 

Chat Noir stood guiltily by the railing of her balcony in front of two broken flowerpots. 

Her eyes narrowed at the culprit, “Chat Noir, did you break my pots?”

“No!” His eyes widened as he stepped forward. “It wasn’t me. It was—I saw a stray cat, yeah a stray on your balcony and I couldn’t have a dirty street cat prowling around my Princess’s balcony so I tried to shoo it away and it broke your pots and—”

Marinette raised her eyebrows, “Chat.”

“It’s true I-I” suddenly he stood ram rod straight and swiped his palm in front of her face, “This is not the chat you’re looking for.”

“What are you doing?”

Chat grinned sheepishly, “It’s Star Wars reference. You know, with Obi Wan and the force. These are not the droids—”

Marinette cut him off with a groan, “Ugh, force! Why is everything about physics?”

“Because physics is life,” he said simply. “I love physics.”

“Oh god you’re such a nerd I,” Marinette stopped, gears turning in her head. “Wait, you love physics?”

Chat nodded, “That’s what I just said.”

“I know that!” she then timidly asked. “So are you good at it?”

“Physics, or charming beautiful women with my high brow humor?”

Marinette rolled her eyes at him, “Physics, you dork. I already know how your so called ‘high brow humor’ works out for you.”

“That hurt Princess,” he deadpanned and then shrugged, “Yeah, I wouldn’t say I’m too bad at it, why?”

Marinette grabbed his hand and led a surprised Chat Noir down into her room.

“Woah there Princess, that’s quite a grip you’ve got there,” he said. “You know, normally I’d prefer to take a beautiful woman such as yourself out on a proper date before being led to the bedroom.”

“Shut up Chat,” Marinette scolded lightly. “I’m seriously in trouble. I need help with physics otherwise I’ll fail the class and I won’t pas the bac and I’ll never get into design school and I’ll have to live in a cardboard box under a bridge on the Seine and freeze to death in the winter.”

Chat stared at her, “Wow.”

“Please help.”

Chat straightened up, puffing out his chest a bit, “Well, I can’t leave a beautiful damsel in distress now, can’t I.”

“Great!” Marinette brought her textbook and sat down cross-legged on the ground while Chat looked over her shoulder on the chaise. “I need help on number seven. Like, I get that the racetrack has friction so the ball slows down at some point but I don’t know how to find the speed it needs to go over the loop without falling down.”

“Hmm,” Chat’s eyes scanned the problem. “You’ve actually set the equations up correctly, but your height is wrong. You have to account for the ball’s radius.”

Marinette’s eyes widened, “Of course!”

She hastily erased her incorrect height and plugged in the new value, punching numbers into her calculator along the way.

“Thanks, Chat.”

“Anytime, Princess.”

“Don’t make promises you can’t keep, chaton,” she warned. 

“I’m serious Mari,” he replied. “I’d love to help you out with physics whenever I can.”

Marinette beamed at him, “Thank you Chat.”

“It’s my pleasure, Princess.”

He watched her circle the correct answer and move on to the next question. 

“Does this mean you’re not mad about the pots?”

“Don’t push your luck, chaton.”

“Can I at least have a cookie?”

“Chat.”


	2. Cats Always Land on Their Feet

**Summary for the Chapter:**

> Lesson 2: Torque and Angular Motion

**Notes for the Chapter:**

> *Ladynoir intensifies*

“I bet you I can jump over this building,” Chat challenged excitedly. 

Ladybug sighed. Although her partner was his usual bubbly self, she was too wound up today to entertain his animated personality. The two of them were perched on a rooftop side by side along the Parisian skyline watching the sun swirl colors into the dusty sky. 

“Don’t you ever get scared of the idea that one day you might miss a step and become a Jackson Pollock painting on la Rue de Martyrs?”

“Then I would be immortalized as a martyr of art,” Chat replied grinning.

“You’re incorrigible.”

“And you love it. Besides,” he continued, musing, “lets say these suits weren’t virtually indestructible. If I have to deal with the purring, the catnip, and the incessant need to scratch my back every goddamn second, then I should also be able to seemingly defy the laws of physics through angular momentum.”

Ladybug, who was trying to tune out her partner in an effort to relax a bit before she had to go home and dive back into her homework, immediately sat up straight, “Did you say angular momentum?”

“Yeah, why?” Then, Chat gasped. “My lady, are you secretly a physics nerd too?”

“Oh god I wish, everything would make so much more sense then. I’m taking physics right now and I swear on my kwami it’s the most unintuitive thing I’ve ever tried to learn, and I swing through the city on a yo-yo. We just started torque and angular momentum and I can’t do it. I just started getting the hang of regular force, but now I have to deal with angles and sides and it’s just too much Chat, I can’t do it.”

“Bugaboo, your entire existence depends on physics. Just wait until you get to pulleys and tension. Everything will make sense to you then.”

“But I need to know torque now,” Ladybug cried softly in frustration. “I’ve got a whole ton of homework problems to go through at home that I don’t know how to do and I really don’t want to do them.”

“I know the feeling,” Chat sighed, patting Ladybug’s shoulder. “I can’t really help you you’re your homework right now but, if you think about torque with cats, it might make more sense.”

“Anything will help,” Ladybug pleaded. 

“Okay so when a cat is falling,” Chat began, “they don’t have any external torque right?”

“Um,”

“Is there an outside torque acting on the cat as it’s falling?”

“Gravity?”

“Gravity’s a linear force. Torque changes the angular motion.”

“Then, no?”

“Exactly,” Chat nodded. “That’s why physicists were so confused, because cats rotate without any external torque. So they figured that cats must have been doing something fancy to rotate, and they were right. Turns out, cats arch their backs a certain way which makes splits their bodies into two parts rotating in opposite directions. Are you with me?”

“I think so,” Ladybug replied, eyebrows furrowed in concentration. 

“So they have two different rotations, which gives equal but opposite angular momentums. But since they’re still one body, the momentums cancel out, giving a net angular momentum of zero.”

“Wait, I’m confused, where does torque come into this?”

“Well angular momentum is caused by torque,” Chat explained. “So when the cat arches its back, it’s causing internal torque, I guess you can call it, which gives two equal but opposite angular momentums that cancel. So the rotation is caused by what the cat is doing, not its external environment.”

Ladybug stared at him.

“Cats do a few more things with their paws to manipulate angular velocity and inertia but the gist of it is that internal angular momentum causes cats to rotate even though the net angular momentum is zero.”

A beat of silence passed before Ladybug said, “I still don’t get it.”

Chat sighed, “It would make more sense if I had a whiteboard or if we could do a demonstration or—”

“Not a bad idea kitty,” Ladybug replied right before pushing Chat off the roof.

Chat yelped in surprise and arched his back, feeling for his baton, which he had just remembered was on the roof next to him. He slowly spun in he air before landing on all fours on the lower terrace of the building.

“Hmm, I still don’t completely understand it, but I guess cats do always land on their feet,” Ladybug called out from above. 

“That was mean Bugaboo. I could’ve died.”

“It’s okay, you’ve still got about seven more lives,” she teased. 

“And I’ll need all of them and then some if I’m going to be with you,” Chat called out. “Could you toss down my baton?”

“I’ll do you one better,” she replied, and cast her yo-yo down below.

“Well well well,” Ladybug remarked, “Looks like I’ve caught a catfish.”

“Very funny my lady,” Chat responded dryly. 

“I try.”

“Well, attempted murder aside, I’m sorry I couldn’t be more help with physics.”

Ladybug shrugged, “It’s okay, I’ll try to figure it out.”

“Is there anyone in the class that you can ask for help from?” Chat suggested.

“Yeah,” Ladybug replied softly, feeling her cheeks heat up slightly. 

“Oh?” Chat raised an eyebrow. “My lady, you’ve gotten all red!”

“Shut up.”

“Do you have a crush?”

“Chat.”

“And are they in your physics class?”

“I said shut up.”

“What?” Chat replied. “I think it’s adorable. What’s their name? What’re they like? And what’s their blood type so I can let the nearest hospital know when I’m done with them.”

“Chat!”

“What? Can’t I make sure my best friend is being taken care of by someone who deserves her?”

“Well if pigs fly and we actually end up dating, you’ll be the first to know,” Ladybug promised.   
“Good.”

“Now let’s talk about you,” Ladybug smiled slyly. 

Chat’s eyes narrowed nervously, slightly taken aback by the sudden shift in conversation, “What about me?”

“What were you saying earlier about you being able to purr?”

**Notes for the Chapter:**

> Hi everyone! Hope you enjoyed this second chapter!
> 
> So I've actually finished my physics class but I love the idea of this story so much that I'm going to keep writing this anyway. Besides, it'll be good review for the MCAT. That being said, these chapters will all go up without a beta reader and it won't be edited since they're just for fun, not serious pieces. Art on Ice, my other multi-chapter fic, is the more serious one and I'm knee deep in story building and figure skating research on that one right now.
> 
> If you want to talk about physics in the comments and maybe learn a bit more about torque and angular momentum, feel free to leave a comment below. Or just say hi if you'd like as well. 
> 
> Thank you so much for reading! Hope you're having a good day!
> 
> -Liz
> 
> *Questions, comments, concerns? Feel free to message me on Tumblr at lizzrossstories

**Author's Note:**

> Hi everyone!
> 
> As some of you may know, I'm currently dying because I decided to take a 10 week accelerated physics course to fulfil my medical school prerequisites (yay life goals). Because physics is a literal demon from hell and I don't have a beautiful blond model with green eyes running around in a magical catsuit to help me with my homework, I decided to let Marinette benefit from it instead. 
> 
> I'll be sticking close to the curriculum that my class is following and spend time in chapters actually trying to explain concepts I learned in class as a way to study the material. If anyone else is struggling with physics, I hope this fic can provide you with a little bit of humor to help you through it, and hopefully present the material in a different way.
> 
> Also! You can find me on tumble at lizzrossstories if you wanna chat about physics or ML or anything else!
> 
> Thanks for reading!
> 
> -Liz


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